Force sensors, commonly known as transducers, can convert an applied mechanical pressure, acceleration, strain, or other force into an electrical output signal. Piezoresistive sensors are force sensors that use the piezoelectric effect to measure pressure, acceleration, strain, or other force by converting the force input to an electrical output signal. Traditional force sensors are capable of measuring only the compressive force component of an applied force, and are incapable of measuring the shear force component simultaneously.
Diabetes mellitus (DM) is a prevalent disease. In Hong Kong, China, for example, approximately 15% of the population suffers from DM. Of these DM patients, about 5% of them suffer from “diabetic foot” complications. Moreover, the pressure points on the foot may cause pressure ulcers associated with diabetic foot. Shear force is a key factor that may cause pressure ulcers, in addition to the pressure generated by normal force.
Consequently, it is desirable to manufacture a force sensor that can measure both the shear force component as well as the compressive force component from an applied force. It is also desirable to manufacture a 2-D force sensor array for pressure mapping applications, for example, one that is useful in preventive and predictive diagnosis for diabetic foot and pressure ulcer problems.